Aluminum brazing is a process of joining two pieces of aluminum together using a filler metal with a lower melting point than the base metals. The filler metal is melted and drawn into the joint by capillary action, and hardens as it cools to create a strong bond between the two pieces of aluminum.
But just how strong is that bond? Let's take a closer look.
Aluminum Brazing vs. Welding
First, it's important to understand the difference between brazing and welding. Both methods involve using heat to join two pieces of metal together but they differ in how that heat is applied. With welding, an electric arc is used to generate enough heat to melt both the base metals and the filler metal, which are then drawn together as they cool and harden.
Brazing, on the other hand, uses a torch or furnace to heat only the filler metal until it melts. The melted filler metal is then drawn into the joint by capillary action, meaning it flows into any spaces or cracks between the two pieces of metal and hardens as it cools to create a bond between the two pieces.
Brazing can be used on metals with dissimilar compositions, such as aluminum and steel, whereas welding can only be used on metals with similar compositions.
The Strength of Aluminum Brazing
Now that we understand how aluminum brazing works, let's take a look at how strong the resulting bond actually is. Laboratory testing has shown that properly executed aluminum brazed joints can have tensile strengths exceeding the base metals being joined, meaning the joint itself is stronger than either piece of metal on its own!
In fact, in many cases aluminum brazed joints are just as strong, if not stronger, than welded joints. That's because when base metals are welded together, their properties change in the area where they were joined (known as the "heat affected zone").
Those changes can weaken the joint over time and make it more susceptible to fracture under stress.
However, because brazing doesn't alter the properties of the base metals being joined, brazed joints are typically much stronger and more durable than welded joints making them ideal for critical applications where strength and reliability are paramount.
Conclusion:
Aluminum brazing is a process of joining two pieces of aluminum together using a filler metal with a lower melting point than the base metals. The filler metal is melted and drawn into the joint by capillary action and hardens as it cools to create a strong bond between the two pieces of aluminum.
Laboratory testing has shown that properly executed aluminum brazed joints can have tensile strengths exceeding the base metals being joined, meaning the joint itself is stronger than either piece of metal on its own! In many cases, aluminum brazed joints are just as strong—if not stronger—than welded joints because brazing doesn't alter the properties of the base metals being joined like welding does. So if you're looking for a strong and reliable joint for your next project, give aluminum brazing a try!
Relevant article: Difference between Soldering and Welding